IT Chapman NR Walkden JP Graves C Wahlberg
Sheared toroidal rotation is found to increase the ideal external kink stability limit, thought to be the ultimate performance limit in fusion tokamaks. However, at rotation speeds approaching a significant fraction of the Alfv´en speed, the toroidal rotation shear drives a Kelvin-Helmholtzlike global plasma instability. Optimising the rotation pr…
PublishedF. Militello W.Fundamenski V. Naulin A.H. Nielsen
The L-mode interchange turbulence in the edge and Scrape Off Layer of the tight aspect ratio tokamak MAST is investigated numerically. The dynamics of the boundary plasma is studied using the 2D drift-fluid code ESEL, which has previously shown good agreement with large aspect ratio machines. In this context, a MAST-TCV comparison is presented in o…
PublishedC. Arnas C. Pardanaud C. Martin P. Roubin G. De Temmerman et al.
Among dust particles of various origins collected in the MAST vessel, large quantities of carbon nanoparticles are observed. They are produced in the coldest plasma regions from the nucleation of carbonaceous species originating from physical and chemical erosion of the graphitic plasma facing components. On the other hand, laboratory plasmas studi…
PublishedL W Packer M Gilbert S Hughes S Lilley R Pampin J-C Sublet
In support of the technological requirements for fusion, the UK fusion technology programme is conducting several experiments using the ASP DT neutron irradiation facility at AWE Aldermaston. The present experimental programme covers two key areas of technology development: improving the quality of nuclear cross-section data required for fusion-rel…
PublishedR. V. Bravenec J. Candy M. Barnes C. Holland
Verification of nonlinear microstability codes is a necessary step before comparisons or predictions of turbulent transport in toroidal devices can be justified. By verification we mean demonstrating that a code correctly solves the mathematical model upon which it is based. Some degree of verification can be accomplished indirectly from analytical…
PublishedS. Queyreau J. Marian M. R. Gilbert B. D. Wirth
In the traditional picture of plasticity in bcc metals, edge dislocations have been assumed to play a minor role due to their high mobility with respect to screw dislocations, which then control plastic flow. 1 2 111{110} edge dislocations indeed fit this description, as it has been shown by way of numerous atomistic simulations. However, 1 2 111{1…
PublishedI.N.Chugunov V.G.Kiptily A.E.Shevelev D.B.Gin
Gamma-ray spectrometry provides diagnostics of fast ion behavior in plasmas of large tokamaks. Information acquiring with the gamma-ray diagnostics gives possibility to identify and distinguish simultaneously presence of fast alpha-particles and other ions (H, D, T, 3 He), to obtain its relative densities and also to perform tomographic radial prof…
PublishedYu. F. Baranov C. D. Challis A. Ekedahl M. Goniche K. Kirov et al.
Mechanisms of arc formation have been analyzed and the critical electric fields for the multipactor effect calculated, compared to the experimental values and found to be within the normal operational space of the LH system on JET. It has been shown that the characteristic electron energy (20-1000)eV for the highest multipactor resonances (N=4-9) a…
PublishedM.Yu. Lavrentiev S.L. Dudarev D. Nguyen-Manh
Magnetic Cluster Expansion model is developed for bcc Fe-Cr alloys, and applied to the investigation of magnetic properties of these alloys for a broad interval of concentrations ranging from pure Fe to pure Cr, and for a broad interval of temperatures extending well over 1000 K. Finite-temperature configurations simulated using the Magnetic Cluste…
PublishedV. Igochine I. T. Chapman V. Bobkov S. Günter M. Maraschek D. Moseev G. Pereversev M. Reich J. Stober Asdex Upgrade Team
It is often observed that large sawteeth trigger the neoclassical tearing mode (NTM) well below the usual threshold for this instability. At the same time, fast particles in the plasma core stabilize sawteeth and provide these large crashes. The paper presents results of first experiments in ASDEX Upgrade for destabilization of fast particle stabil…
Published